Solar-Driven Catalytic Wastewater Treatment: A Unified Photonic–Thermal Framework for Advanced Oxidation and Disinfection Mechanisms

Increasing water demand and the rising complexity of wastewater matrices, driven by pharmaceuticals, personal care products, and recalcitrant industrial contaminants, require advanced catalytic solutions capable of efficient mineralization under sustainable conditions. Solar-driven processes have attracted growing attention; however, ultraviolet disinfection, heterogeneous photocatalysis, and photo-Fenton systems are commonly treated as independent approaches without mechanistic integration. This review presents a unified photonic–thermal catalytic framework for solar-driven wastewater treatment, emphasizing the interplay between photon absorption, charge-carrier separation, reactive oxygen species generation, and radical-mediated oxidation pathways. The contributions of ultraviolet, visible, and infrared radiation are analyzed in terms of catalyst activation, persulfate and ozone activation mechanisms, and temperature-enhanced reaction kinetics governed by Arrhenius behavior. Particular attention is given to photothermal effects that modulate surface reaction rates, mass transfer, and catalyst stability. By integrating mechanistic insights with reactor-level considerations, this work provides a rational basis for the design of robust solar catalytic systems with enhanced activity, selectivity, and scalability for real wastewater applications.